Whether you have an existing bike that you would like to have a set-up perfectly or want to purchase a new bike and ensure that it's exactly the right size for you. We have the answer. At Twenty3c we are able to work with you to achieve a perfect position on your bike that is both comfortable and efficient.
We all spend a lot of money on our bikes and cycling, but if the bike is not set up specifically for you, you may not be getting the most out of yourself or the bike and perhaps losing some of that all important power and comfort.
To book your bike fit or discuss your bikefitting needs, call the shop on 01908 260 322.
At Twenty3c we offer 3 levels of bike fits with an option of cleat fitting:
Cleat fitting - £40
Foot assessment & correct cleat positioning on the shoe, this normally takes approximately 1 hour.
1 - Bikefitting.com Static Fit - £35
Bikefitting.com is a well respected static bike fitting system that measures 8 key points of your body which are then fed into a computer to give an accurate bike set-up for your body shape. This fit is ideal for selecting the correct bike size and a starting point to set your new bike to.
A bikefitting.com fit cost £35 - the cost of this fit is refundable if a bike or frame is purchased from Twenty3c.
2 - Twenty3c Bike Setup and Positioning - £90
This fit uses the same principles of the full Retul fit just without using the Motion Capture element. This fit normally takes about 2 hours and is ideal for a rider who wants to improve their existing position or has recently purchased a new bike.
The fit involves - customer flexibility assessment, rider profile, saddle height & position, handle bar reach and drop, lever positioning, pedalling evaluation to ascertain correct power transfer through the pedal, knee tracking, riding positioning to ensure comfort and optimum performance.
3 - 3D Motion Capture Analysis using Retul - £175
How does it work?
Retul is arguably the most accurate bike fit system on the market. Retul uses motion capture technology, i.e. you riding your bike whilst you’re attached to a computer that analyses your position and bike set-up. The data that is produced is sub millimetre accurate and void from human error. The system accurately assesses your position whilst in motion (pedalling your bike) and highlights positional changes that need to be made. This data enables us to set your bike up to achieve your optimal position. During the fit we use a power meter so that we can do 3 separate recordings using 3 incremental power loads. We do this on both sides of your body, so 6 assessments in total. From these 6 assessments we are be able to make the required adjustments to your position which will help with your comfort and performance. Once the adjustments have been made we do a further two assessments one from each side of your body to ensure the changes we have made give the required results.
Using eight (8) anatomical LED markers strategically placed on the wrist, elbow, shoulder, hip, knee, ankle and ball of the foot, the Retül sensor gathers information in real time and transmits it to the PC. In real time.
What makes Retul better than other systems?
Most bike fit specialists fit riders in a static position. This is because the traditional tools of the trade — tape measures and plumb bobs — don’t allow accurate measurements while the rider is pedalling. Retül captures the rider’s position relative to his pedalling motion, and therefore creates the most realistic replication of the actual pedal stroke and body position when out on the road and trails.
Measurements made by traditional tools have one thing in common: they are subject to human error and therefore can be devastatingly inaccurate. Even slight inaccuracies can completely change the rider’s feel after a ride. The general rule is that if you feel pain, something can probably be changed to eliminate that pain. Retül uses motion capture technology that accurate to within less than a millimetre, creating true objective data which can be utilised by the right fitter for the perfect biomechanical fit.
Bike fit data collected in a traditional 2-dimensional plane (i.e. video based systems) is fairly limited because the fitter can only look at one view at a time and those views stand as independent reference points. In order to make the best fit recommendations, the fitter must realise that the front and side view are actually interdependent reference points. In other words, the front and side view must be viewed simultaneously in 3-D in order to see how all the applicable movements of the body are working together. Retül uses 3-dimensional views to see just these precise mechanics to be able to see knee extension (from side view) in relation to knee wobble (from front view) in order to make the best decisions on adjustments to the cyclist.
How long does it take?
A Retul fit usually takes 2-3hrs depending on the adjustments required to your existing setup.
How much does it cost?
A Retul fit costs £175 for the initial fit and an additional £75 for a second fit.
Book your bike fit today by calling us on 01908 260 322 or alternatively email us at
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At the time of booking we will take a non-refundable deposit of £50, and we have also introduced a charge of £25 if you reschedule your fit less than 7 days before the booking.
What do I need to bring?
All you need is your bike, riding kit and your self. We have changing facilities on site so you can get changed once you arrive at the shop.
Twenty3c & Bike Fitting
At Twenty3c we have over 20 years experience of bike fit/bike building knowledge and have helped hundreds of customers enjoy their cycling through their personal bike set-up and quality bike builds. Alan has built a reputation as one of the country’s leading bike build specialists through his knowledge, experience and attention to detail. Alan has built hundreds of bikes for elite level athletes, sportive and recreational riders. Alan works closely with each customer/athlete to ensure that their bike fit is correct not only when walking out the door but over an unlimited period of time. Bike fitting is undoubtedly a skill but will not work without a personal, ongoing relationship with each rider, it is you that will be riding your bike and the feedback that you provide is invaluable to achieve the perfect bike fit. What you will get is not just a state of the art bike fit but your very own bike fit consultant that will work with you to help you achieve your goals.
Alan travelled to the Retul fit studio in Denver Colorado to be trained by Bio mechanist Todd Carver, MS, one of the world's most experienced bike fitters using 3-D motion capture technology. Alan spent time with Todd fitting a number of clients and gained invaluable knowledge to add to his extensive bike building skills.
Customer Testimonials
"I had read about the Retul bike fitting on the internet and was attracted by the fact that it was a dynamic computer assessment as opposed to a static measurement system. Alan and Ceri were both informative and friendly. I was particularly impressed by the fact that it was emphasised to me that this should not be viewed as a one off fitting and should be part of an ongoing relationship until I get the fit exactly to my liking.
By using the system, my feedback and their expertise we were able to obtain a starting point for me to develop. I was made aware that as I got fitter, more flexible and possibly lighter that my requirement would most likely change which is the reason for emphasis on an ongoing relationship. I consider the Retul system to be arguably the best system on the market at present and highly recommend Alan and Ceri for their knowledge of the system, expertise and customer service. I have subsequently had other things done on my bikes and trust them very highly to undertake mechanical repairs or upgrades on the same."
B.H - UK
I am writing to thank you for creating my ‘Retul cycle fit experience’ and update you of my progress since.
For me personally, my cycle fit experience delivered everything it promised:
Kind and friendly atmosphere.
Explanation of the process in layman terms.
Total involvement throughout the fit process.
Fit process carried out using my bike.
Analysis using the latest 3D technology whilst cycling.
Acknowledged aspects of my existing riding position that worked.
Adjustments explained and carried where necessary on site with further evaluation and confirmation.
No change for change sake.
Explanation of how my body would adapt to the new riding position.
Detailed personal bicycle setup report to take away.
Most importantly; I left with a comfortable and efficient riding position.
Following the adjustment made to my riding position; lowering my handlebars by 15mm, I no longer suffer from stiff shoulders or neck discomfort whilst riding.
I would recommend Twenty3c and the Retul cycle fit experience to all cyclists of any level and ability to further and prolong their enjoyment of cycling.
It’s refreshing to ache as a result of cycling rather than because of cycling.
